Abstract: Objective To investigate the influence and mechanism of lysophosphatidic acid and RhoA/ROCK2 signal pathway on proliferation of breast cancer cell. Methods After breast cancer cell(MDA-MB-231) was treated with different concentration of LPA, the proliferation of MDA-MB-231 was observed and recorded by cell count method every of 24h. MDA-MB-231 was treated with optimal concentration of LPA and observed the effect of Rho kinase inhibitor(Y-27632) on LPA-induced proliferation. The activity of RhoA was tested by Pull-down way. The protein expression of RhoA and ROCK2 were determined by Western blot. Results LPA could promote MDA-MB-231 proliferation in a time and dose-dependent manner (P<0.05). ROCK inhibitor could significantly inhibit LPA-induced cell proliferation(P<0.05). The activity of RhoA and expressionof RhoA, ROCK2 were enhanced significantly affected by LPA (P<0.05). However Y-27632 markedly decreased LPA-induced the increase of RhoA activity and protein expression of RhoA and ROCK2 (P<0.05). Conclusions LPA may promote breast cancer cell proliferation through regulating by RhoA/ROCK2 signal pathway. It provides a new idea for breast cancer clinical treatment.

Key words: lysophosphatidic acid, breast cancer, proliferation, RhoA/ROCK2 signal pathway